Field
This disclosure is directed to syringes having temperature modulation capabilities, particularly with regard to changing the temperature of the material being ejected from or injected into the syringe. In a specific embodiment of this invention, the syringe comprises a phase transition composition which is to be maintained in one phase within the syringe chamber and ejected in a different phase from the syringe.
State of the Art
Many compositions require a temperature change before injection into in a subject. In one case, pharmaceutical formulations suitable for, e.g., intraveneuos injection, are often unstable at room or body temperatures and must be refrigerated to ensure proper efficacy for the administered drug. However, as is apparent, these compositions are typically allowed to reach at least room temperature prior to administration and the time required to achieve room temperature delays administration.
Likewise, phase transition compositions have been disclosed for use in treating patients. In one embodiment, phase transition compositions can be used to fill a lumen in the patient. Such lumens include blood vessels as during surgical procedures, vas deferens to effect male sterilization, fallopian tubes to effect female sterilization, intestinal tracts, and the like. The phase transition composition can be introduced in its liquid phase and then allowed to phase transition to its solid phase when exposed long enough to body temperature. See, for example, United States Patent Application Publication No. 2007/0191768 and U.S. Pat. No. 7,160,931.
One particular embodiment that has drawn significant interest is the use of phase transition compositions during surgical procedures such as anastomosis. See, for example, United States Patent Application Publication Nos. 2008/0045985 and 2008/0031847.
One limitation with using phase transition compositions is that their transition from a solid to a liquid phase or from a liquid to a solid phase occurs over a temperature range. The broader the temperature range, the more likely that the composition will stay in the “undesired” phase before converting to the “desired” phase. This delay may result in difficulty for the surgeon to assess whether the phase transition has been completed prior to initiating the surgical procedure. When a poloxamer is used in the phase transition composition, one attempt to minimize this delay has been to purify the poloxamer to a narrow molecular weight range such that the phase transition temperature will occur over a narrower temperature range. See, for example, United States Patent Application Publication No. 2008/0031847.
Notwithstanding the benefits alleged by the approach, the surgeon is still left with the task of evaluating when the composition has completed its phase transition. If a surgical procedure is initiated before phase transition is complete, complications will arise. For example, United States Patent Application Publication No. 2008/0031847 recites use of a phase transition composition during bowel resection. If the phase transition composition is not completely in the solid phase, cutting the bowel can result in septicemia.
In view of the above, there is an ongoing need to develop means to ensure in vivo delivery of a phase transition composition substantially in one phase or the other. It would be beneficial if such means could be used to control the temperature of any composition delivered from a syringe such that the attending clinician could immediately inject that composition into the patient.
It should be noted that all patents, patent applications, and literature references described herein are incorporated by reference in their entirety.